The present invention generally relates to genlock (GENERATION LOCK) devices and, more particularly, to a genlock device having a function for storing a genlock state and/or a function for judging and alerting the genlock state.
A genlock device is incorporated in various apparatuses which perform video processing etc. and are disposed in, for example, a studio in a broadcast station, an outside broadcast van, or the like.
FIG. 1 is a diagram for schematically explaining a genlock system and FIG. 2 is a schematically functional block diagram of a video signal generator 12.
As shown in FIG. 1, the genlock system includes a reference signal generator 11, video signal generators 12 and 13, and a terminator 14. The reference signal generator 11 generates a reference signal (for example, NTSC black burst (BB) signal: EXT_REF), and the reference signal (EXT_REF) is inputted to both of the video signal generators 12 and 13. Each of the video signal generators 12 and 13 generates a video signal synchronized with the reference signal (EXT_REF) and outputs it. Thus, since the video signal outputted from each of the video signal generators 12 and 13 is synchronized to the common reference signal (EXT_REF), it is convenient to process the video signal to merge images outputted from the video signal generators 12 and 13.
As shown in FIG. 2, the video signal generator 12 includes a genlock device 21 and a video signal processing device 22. The genlock device 21 inputs the reference signal (EXT_REF), generates a master reference clock signal (MAS_REF_CLK) synchronized with the reference signal (EXT_REF), and outputs it. The video signal processing device 22 generates an image signal synchronized with the reference signal (EXT_REF) based on the master reference clock signal (MAS_REF_CLK) and outputs it.
In addition, a video signal generator similar to the video signal generator 12 shown in FIG. 2 is disclosed in, for example, Japanese Patent Application Laid-Open (JP-A) No. 10-191099 (FIG. 13).